We are seeking a Senior Backend Engineer with deep experience building production-grade RESTful APIs in Python (ideally FastAPI) and designing backend systems that support AI-enabled products. Our services must handle mixed workloads-from low-latency, performance-optimized endpoints to high-latency operations like LLM calls, model execution, and data-heavy workflows-often by leveraging async patterns (event loops, FastAPI lifespans) and background processing (message brokers, workers, retries, idempotency). You’ll work closely with cross-functional partners including Data Scientists, Analytics Engineers, Front-End Engineers, Product Managers, and Designers to define requirements, align on data contracts and APIs, and deliver reliable, scalable backend systems that power our most critical AI initiatives.

Now, if you were to come on board as our Senior Backend Engineer, we’d ask you to do the following:

• Design, build, and maintain RESTful APIs in Python (preferably FastAPI) with clean contracts, strong validation, and excellent developer ergonomics.

• Own backend architecture and design patterns: modular service design, clear separation of concerns, extensibility, and maintainability.

• Build for performance and reliability: optimize request/response paths, implement caching and rate limiting where needed, and ensure predictable behavior under load.

• Implement async-first backend systems: strong understanding of event loops, async I/O, FastAPI lifespans, dependency injection patterns, proper error handling, and safe concurrency.

• Design background processing workflows: offload heavy/high-latency work (LLM calls, model runs, long computations) to queues/workers and message brokers; implement retries, idempotency, and DLQs.

• Operate production services: logging, metrics, tracing, alerting, runbooks, and post-incident learning; drive improvements to reliability and cost.

• Collaborate cross-functionally with Data Science, Analytics Engineering, Front-End, and Product to define API contracts, data requirements, and delivery plans.

• Mentor and raise the bar through code reviews, design reviews, and setting engineering standards (testing, CI/CD, documentation, security).

Think you have what it takes to be our Senior Backend Engineer? Here’s how we’ll know:

• Bachelor’s or Master’s degree in Computer Science, Engineering, or a related STEM field (advanced degree a plus).

• 6+ years of professional backend engineering experience building and operating production services.

• Strong proficiency in Python (OOP is a plus) and SQL, with excellent software engineering fundamentals (testing, code quality, design patterns, system design).

• Proven experience building RESTful APIs-ideally with FastAPI-including strong API design practices (validation, versioning, pagination, error handling, auth).

• Solid understanding of asynchronous programming in Python (event loop, async I/O), including FastAPI lifespans and concurrency best practices.

• Experience designing and running background processing systems (queues/message brokers, workers) with reliability patterns such as retries, idempotency, and dead-letter handling.

• Experience with cloud platforms (AWS and/or GCP) and production operations (logging, metrics, tracing, alerting).

• Experience with containerization and modern deployment workflows (Docker; Kubernetes and infrastructure-as-code tools are a plus).

• Familiarity with event-driven or real-time architectures for service integration is a plus.

• Exposure to AI-enabled backend patterns (e.g., LLM integrations, model execution workflows, semantic search/vector databases) is a plus, but not required.

• Strong collaboration and communication skills, with the ability to influence cross-functional partners and lead technical execution.

• Working knowledge of version control (Git) and agile development practices.

Position Details:

• Position Title: Senior Backend Engineer

• Salary: 120,000.00 - 150,000.00

• Employment Type: Full Time, Permanent

• Perks: Bonus, 4 Weeks Vacation, RRSP Match and more!

• Hybrid: 3 Days a Week - Toronto

In accordance with provincial legislation and our commitment to transparent hiring practices, the compensation range for this position is provided. Final compensation will be determined based on qualifications, experience, and internal equity. Canadian work experience is not required. Please note that artificial intelligence tools are utilized in the applicant screening process.